Changes in blood catecholamines during induction of general anesthesia in patients with post-induction hypotension undergoing laparoscopic cholecystectomy: A single-center prospective cohort study

Background Post-induction hypotension (PIH) often occurs during general anesthesia induction. This study aimed to investigate blood catecholamine levels during induction of general anesthesia in patients with PIH undergoing laparoscopic cholecystectomy. Methods This prospective study included 557 adult patients who underwent laparoscopic cholecystectomy under general anesthesia. PIH was defined as a greater than 20% decrease in systolic blood pressure from the pre-induction value, a systolic arterial pressure of less than 90 mmHg, or both. Plasma concentrations of epinephrine and norepinephrine during the induction of general anesthesia were determined using enzyme-linked immunosorbent assay. Multivariate logistic regression analysis evaluated the association between the clinical factors and PIH. Results Of the 557 patients, 390 had PIH, and the remaining 167 were allocated to the non-PIH group. Changes in blood adrenaline, noradrenaline levels, or both were more pronounced in the PIH than in the non-PIH group (p<0.05). Age, body mass index, a history of hypertension, preoperative systolic blood pressure, and propofol or sufentanil dose were independent predictors of PIH. Conclusion The changes of blood catecholamines in patients with more stable hemodynamics during the induction of general anesthesia are smaller than that in patients with post-induction hypotension. Trial registration ChiCTR2200055549, 12/01/2022.

版本号： 1.0 版本日期：2020.09.07 3 In strict accordance with the inclusion and exclusion criteria, after signing the informed consent form, the anesthesiologist will measure the baseline blood pressure of the patient before the operation, and the non-invasive arterial blood pressure will be used to measure the baseline blood pressure of the patient before the induction.At the same time, the height, weight, BMI, ASA grade, basic disease, and other characteristics of each patient were understood through the clinical digital anesthesia record sheet.The radial artery blood was collected from all patients at three time points before anesthesia induction (T0), after anesthesia induction (T1), and after tracheal intubation (T2).The blood samples of 80 patients were randomly selected for examination, and the changes of blood catecholamine before and after induction were observed, combined with the characteristics of patients before and after operation and the anesthetic use during operation, so as to understand the relationship between the induced hypotension and the above indicators, and provide useful information for disease research.

Observation indicators
(1) The occurrence of hypotension after induction.
(2) Heart rate, systolic blood pressure and diastolic blood pressure (perioperative period) (3) Changes of blood catecholamines in some patients before and after anesthesia induction (4) Use of narcotic drugs.

4、Adverse event observation
4.1 Possible adverse events (1) When blood samples were taken, there were transient palpitations, cold sweats and other dizziness reactions; (2) Postoperative anxiety due to pre-induction evaluation and blood sampling.

Risk prevention and treatment
(1) Pay close attention to the patient's vital signs during sampling, and seek the help of professional psychologist at any time to avoid stress reaction 版本号： 1.0 版本日期：2020.09.07 4 (2) Ask the physical and mental health doctor to conduct psychological counseling, confide and vent to avoid aggravating anxiety.

Review by the Ethics Committee
The protocol, the written informed consent form and the data directly related to the subject were submitted to the ethics committee, and the study was officially carried out after obtaining the written approval of the ethics committee.Inform the Ethics Committee in writing when the study is suspended or completed; Report all changes in the research work (such as the revision of the protocol or informed consent number) to the Ethics Committee in a timely manner, and do not implement these changes without the approval of the Ethics Committee, unless they are made to 版本号： 1.0 版本日期：2020.09.07 5 eliminate the obvious and direct risks to the subjects.In such cases, the Ethics Committee will be informed.
6.2 Informed consent 6.2.1 Procedures for obtaining informed consent The researcher must provide the subject or his legal representative with an easy-to-understand informed consent form approved by the ethics committee, and give the subject or his legal representative sufficient time to consider the study.The subject shall not be included in the group until the signed written informed consent form is obtained from the subject.During the participants' participation, all updated informed consent forms and written information will be provided to the subjects.The informed consent form shall be kept as an important document of the clinical trial for future reference.

7、 Confidentiality measures
The results of the research through this project may be published in medical journals, but we will keep the patient's information confidential according to the requirements of the law.Unless required by relevant laws, the patient's personal information will not be disclosed.When necessary, the government management department, the hospital ethics committee and its relevant personnel can consult the patient's information according to the regulations.

8、 Expected progress and completion date of the research project
February 2022 -November 2022: complete the collection of formal experimental data; November 2022 -January 2023: summarize data and write papers; January 2023 -February 2023: paper revision, submission and publication.

9、 References
[1].Saab, R., et al., Failure to detect ward hypoxaemia and hypotension: contributions of insufficient assessment frequency and patient arousal during nursing assessments.

5. 1
Inclusion of sample content; Patients who underwent simple laparoscopic cholecystectomy from February 2022 to November 2022 in the General Department of Hepatobiliary Surgery and Surgery of the Affiliated Hospital of Southwest Medical University were included.5.2 Statistics and analysis of research dataStatistical analysis was performed using R4.0.5.Categorical variables are expressed as counts and percentages (%), while continuous variables are expressed as mean ± standard deviation or median and quartile ranges.The independent sample t-test was used to compare the parameter values of the two groups, the Mann-Whitney U-test was used to compare the non-parameter values of the two groups, and the chi-square test was used to compare the classified variables.Variables with a p-value ≤ 0.1 were included in the multivariate logistic regression model to identify independent risk factors and then the nomogram of the prediction model was constructed.All tests were two-sided, and the significance level was set at P < 0.05, the ROC curve and the area under the curve (AUC) was drawn and calculated to evaluate the discrimination.Then, the calibration degree of the prediction model was evaluated by Hosmer-Lemeshow test and the calibration curve, and finally the decision curve analysis (DCA) was used to evaluate the clinical net benefit.